Subject: [storm] I_T nexus identifier editorial

From: Mallikarjun Chadalapaka <[email-masked]>
Date: Mon, 21 Nov 2011 15:43:56 -0800

In responding to editorial comments on iSCSI-SAM-4 draft, I have just
noticed a related editorial in the consolidated draft that dates back to RFC
3720.

I_T nexus - a relationship between a SCSI Initiator Port and a
SCSI Target Port, according to [SAM2]. For iSCSI, this
relationship is a session, defined as a relationship
between an iSCSI Initiator's end of the session (SCSI
Initiator Port) and the iSCSI Target's Portal Group. The
I_T nexus can be identified by the conjunction of the SCSI
port names or by the iSCSI session identifier SSID. iSCSI
defines the I_T nexus identifier to be the tuple (iSCSI
Initiator Name + 'i' + ISID, iSCSI Target Name + 't' +
Portal Group Tag).

The parenthetical expression at the end should really have four commas in
it:

(iSCSI Initiator Name + ',i,' + ISID, iSCSI Target Name + ',t,' + Portal
Group Tag).

This is how the mapping table captures the nexus identifier in the
iSCSI-SAM-4 draft.  And it'd be good to have consistency between the two
drafts.  I am assuming it'd be possible to make this tweak during the
authors' 48 hour review before the publication (David/Tom?)

Thanks.

Mallikarjun

---

From: <[email-masked]>
Date: Mon, 21 Nov 2011 19:02:18 -0500

Mallikarjun,

I think that's enough of a technical change that making it now would be a good idea, especially
as we can't send the consolidated draft for publication until the new features (SAM) draft is
ready to go also.

While you're looking at this, please double check the alignment of these names and identifiers
with the material in Annex A of SAM-5 (e.g., both the ISID and TPGT are documented there as
hex numbers with a '0x' prefix).

Thanks,
--David (storm WG co-chair).

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of Mallikarjun Chadalapaka
> Sent: Monday, November 21, 2011 6:44 PM
> To: [email-masked]
> Subject: [storm] I_T nexus identifier editorial
> 
> _______________________________________________
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---

From: Mallikarjun Chadalapaka <[email-masked]>
Date: Tue, 22 Nov 2011 10:48:30 -0800

David,

I have just taken a quick look at Table A.6 on SAM-5 Annex A.  I think it
has a potential issue: the verbiage restricts the hex prefix to just the
lower case, i.e. "0x".  In contrast, RFC 3720 and the consolidated draft
explicitly allow either upper or lower case - "0x" or "0X" hex prefix.  I
believe the best place to fix this disconnect would be in the SAM-5 spec.

It also brings up the question of missing "0x" in the iSCSI I_T nexus
identifier description of RFC 3720.  I can only surmise we must had
considered it "obvious" in the past as the previous bullet in the text
requires it for port names, and then defines that I_T nexus identifier is
based on port names.  Regardless, It'd be good to fix this discrepancy now.
So the new verbiage would be:

I_T nexus - a relationship between a SCSI Initiator Port and a SCSI Target
Port, according to [SAM2]. For iSCSI, this relationship is a session,
defined as a relationship between an iSCSI Initiator's end of the session
(SCSI Initiator Port) and the iSCSI Target's Portal Group. The I_T nexus can
be identified by the conjunction of the SCSI port names or by the iSCSI
session identifier SSID. iSCSI defines the I_T nexus identifier to be the
tuple (iSCSI Initiator Name + ",i,0x" + ISID in text format, iSCSI Target
Name + ",t,0x" + Portal Group Tag in text format) - an upper case hex prefix
"0X" may alternatively be used in place of "0x".

As for publishing a new version, I could try to get to it soon..... (the
main challenge is the text conversion process: it creates a couple of
hundred broken alignments, and ASCII figure skews, most of which are caught
by idnits and need manual fixing, :( )

Thanks.

Mallikarjun

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] 
Sent: Monday, November 21, 2011 4:02 PM
To: [email-masked]; [email-masked]
Cc: [email-masked]
Subject: RE: [storm] I_T nexus identifier editorial

Mallikarjun,

I think that's enough of a technical change that making it now would be a
good idea, especially as we can't send the consolidated draft for
publication until the new features (SAM) draft is ready to go also.

While you're looking at this, please double check the alignment of these
names and identifiers with the material in Annex A of SAM-5 (e.g., both the
ISID and TPGT are documented there as hex numbers with a '0x' prefix).

Thanks,

> noticed a related editorial in the consolidated draft that dates back 
> to RFC 3720.
> 
> I_T nexus - a relationship between a SCSI Initiator Port and a SCSI 
> Target Port, according to [SAM2]. For iSCSI, this relationship is a 
> session, defined as a relationship between an iSCSI Initiator's end of 
> the session (SCSI Initiator Port) and the iSCSI Target's Portal Group. 
> The I_T nexus can be identified by the conjunction of the SCSI port 
> names or by the iSCSI session identifier SSID. iSCSI defines the I_T 
> nexus identifier to be the tuple (iSCSI Initiator Name + 'i' + ISID, 
> iSCSI Target Name + 't' + Portal Group Tag).
> 
> (iSCSI Initiator Name + ',i,' + ISID, iSCSI Target Name + ',t,' + 
> Portal Group Tag).
> 
> iSCSI-SAM-4 draft.  And it'd be good to have consistency between the 
> two drafts.  I am assuming it'd be possible to make this tweak during 
> the authors' 48 hour review before the publication (David/Tom?)
> 
> Thanks.
> 
> Mallikarjun
> 
>

---

From: <[email-masked]>
Date: Tue, 22 Nov 2011 15:05:30 -0500

> believe the best place to fix this disconnect would be in the SAM-5 spec.

I agree - RFC 3720 is the normative reference for this format (to be superseded by
the consolidated iSCSI draft), whereas Annex A of SAM-5 is informative.  I suspect
that allowance of both upper case and lower case 'x' was missed in putting Annex A
of SAM-5 together and a corrective proposal to T10 is in order.  I'll work offline
with some other T10 participants to pull that corrective proposal together.

The current plan is to submit both the iSCSI consolidated draft and iSCSI new
features (SAM) draft to our AD and the IESG sometime in December.

Thanks,
--David

> From: Mallikarjun Chadalapaka [mailto:[email-masked]]
> Sent: Tuesday, November 22, 2011 1:49 PM
> To: Black, David; [email-masked]